1. Field
One or more embodiments of the present invention are directed to an organic light-emitting device.
2. Description of the Related Art
Organic light-emitting devices (OLEDs) are self-emitting devices, which have wide viewing angles, high contrast, quick response, high brightness, low driving voltage characteristics, and can provide multicolored images.
A typical OLED has a structure including an anode, a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and a cathode which are sequentially stacked on a substrate. In this regard, the HTL, the EML, and the ETL are organic thin films formed of organic compounds.
An operating principle of an OLED having the above-described structure is as follows.
When a voltage is applied between the anode and the cathode, holes injected from the anode move to the EML via the HTL, and electrons injected from the cathode move to the EML via the ETL. The holes and electrons recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted.